Genetic counseling: Hypotonia - Developmental Delay
Hypotonia - Developmental Delay Contracting *Introductions, acknowledge prior contact *Assess main concerns of patient *Why are they visiting Genetics today? **What do they hope to gain from the session? ***explore desire to have a diagnosis ****mother previously mentioned that they had come to terms with not having a diagnosis *Overview of today's session **Restate patient's concerns **Medical history, family history, physical exam, genetics, recurrence risk, testing options and limitations Pediatric Intake *Family History **any relatives with hypotonia? developmental delay or learning disabilities? MR? -- no to all **history of infant deaths or miscarriages? birth defects? -- no **diabetes? cancer? thyroid prolems? heart problems? respiratory problems? genetic conditions? -- no to all **consanguinity? -- no Differential Diagnosis *Canavan disease **autosomal recessive **characterized by developmental delays by age 3-5 months, severe hypotonia involving "head lag", and inability to sit, walk, or speak **hypotonia eventually changes to spasticity and help with feeding is necessary **macrocephaly **Testing ***urine analysis for concentration of N-acetylaspartic acid (NAA) ****increased in affected patients ***blood analysis for levels of aspartoacylase enzymatic activity ****often unmeasurable in affected patients Myotonic Dystrophy **autosomal dominant **incidence of 1/20,000 **suspected in infants with hypotonia, facial muscle weakness, generalized weakness, club foot, and respiratory insufficiency or failure **Mild -- characterized by cataract and mild myotonia **Classic -- characterized by muscle weakness and wasting, cataracts, myotonia, cardiac conduction abnormalities **Congenital -- hypotonia, severe generalized weakness at birth, often have respiratory problems and early death, MR common **Testing ***DNA analysis is 100% sensitive ****detects an expansion of the CTG trinucleotide repeat in the DMPK gene (19q13) ***> 37 repeats is abnormal ***> 50 repeats are symptomatic ***> 1000 repeats often seen in congenital type *Cerebellar Ataxia **most types have onset in adulthood **Spinocerebellar Ataxia 7 -- failure to thrive and loss of motor milestones, loss of vision **Spinocerebellar Ataxia 8 -- common initial symptoms are scanning dysarthria with a characteristic drawn-out slowness of speech and gait instability, hyperactive tendon reflexes ***onset can be as early as one year old ***Testing -- CTA/CTG expansion in the SCA8 gene (13q21) can be detected via DNA analysis *Aicardi syndrome **X-linked dominant inheritance **characterized by the partial or complete absence of the corpus callosum (the structure that links the 2 hemispheres of the brain), infantile spasms, mental retardation, and an ocular abnormality called lacunae (lesions) of the retina of the eyes **may be associated with other brain defects such as microcephaly or porencephalic cysts (cerebrospinal fluid-filled cavities or gaps in the brain) **onset generally begins between the ages of 3 and 5 months *Myasthenia gravis (familial infantile) **autosomal recessive **characterized by respiratory and feeding difficulties in an infant **absence or weakness of the ocular muscles is also characteristic *Familial Dysautonomia **characteristics include lack of tearing, emotional lability, paroxysmal hypertension, increased sweating, cold hands and feet, corneal anesthesia, erythematous blotching of the skin, and drooling **the absence of the fungiform papillae of the tongue is also characteristic **scoliosis is often severe and neuropathic joints of the Charcot type may develop **Ashkenazi-Jewish heritage is common Previous Testing *chromosomal testing done previously -- results normal Management and Treatment Psychosocial Issues **How important is a diagnosis to you? **If the visit to Genetics does not result in a diagnosis, what will this mean to you? **Are you worried about your child having a "label"? *Financial concerns *Support Network **do attend meeting of "Mother of Special Children" each month **support from family? friends? church? *Educational concerns Support Groups and Resources *Mothers of Special Children :www.mothersofspecialchildren.com :meet the second Monday of each month at 7:30 :Hyde Park Bethlehem United Church :Hyde Park and Madison Road *Ohio Coalition for the Education of Children with Disabilities :www.ocecd.org :Director: Margaret Burley :Co-Director: Lee Ann Derugen :Executive Office :165 West Center Street, Suite 302 :Marion, OH 43302-3741 :Phone (740) 382-5452 or (800) 374-2806 (in Ohio) :Fax (740) 383-6421 :E-mail: ocecd@gte.net *March of Dimes Birth Defects Foundation :1275 Mamaroneck Avenue :White Plains, NY 10605 :email: resourcecenter@modimes.org :internet: http://www.modimes.org :Tel: 914-428-7100 888-MODIMES (663-4637) :Fax: 914-428-8203 References *www.geneclinics.org (Canavan syndrome, Myotonic Dystrophy, Cerebellar Ataxia) *Smith's Recognizable Patterns of Human Malformation *OMIM #304050 (Aicardi syndrome), #254210 (Myasthenia gravis), #223900 (Familial Dysautonomia) *National Institute of Neurological Disorders and Stroke **Aicardi syndrome information page http://www.ninds.nih.gov/health_and_medical/disorders/aicardi.htm Notes The information in this outline was last updated in 2002. 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